Fluid enclosure and methods related thereto

ABSTRACT

Embodiments of the invention relate to a fluid enclosure including a structural filler and an outer enclosure wall conformably coupled to the structural filler. Embodiments of the present invention further relate to a method of manufacturing a fluid enclosure. The method includes conformably coupling an outer enclosure wall to a structural filler.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/489,136, filed on Jun. 22, 2009, which application is a continuationof U.S. patent application Ser. No. 11/473,591, filed on Jun. 23, 2006,now U.S. Pat. No. 7,563,305, which applications are incorporated hereinby reference in their entirety.

TECHNICAL FIELD

Embodiments of the present invention relate to fluid enclosures. Morespecifically, embodiments relate to fluid enclosures for small or microscale systems.

BACKGROUND

Currently, fluid enclosures are designed and built independently of thefluid being stored, or of any storage material that would be insertedwithin the enclosure. In its simplest form, a conventional pressurevessel can be used to contain a fluid, such as a compressed gas or aliquefied gas. The pressure vessel must be designed to accommodate themaximum pressure of the fluid without failure. Such simple designapproaches can be extended to incorporate a storage material by fillingthe pressure vessel with storage material. In this case, the pressurevessel must now withstand the fluid pressure, as well as the stressinduced by the force of the storage material exerted on the internalpressure vessel walls. Presently, these vessels tend to be of acylindrical shape.

When very small storage systems are required, or when irregular (i.e.non-cylindrical) shapes are called for, the overall approach ofemploying conventional pressure vessels becomes problematic. In order tocontain the internal pressures and mechanical stresses induced by astorage material, wall thickness and material properties of theenclosure must be sufficient to prevent rupture. Material propertiesconsidered include tensile strength, ductility, material compatibility,enclosure geometry, stress factors, etc. As a result, the range ofmaterials that can be used to construct the enclosure is limited, andonly vessel geometries which do not overly amplify the internalpressures as enclosure stress can be considered.

Challenges to fluid enclosure design are amplified when incorporated insmall systems, such as in a small or micro scale fuel cell. In smallsystems, fluid enclosure wall thickness consumes a significant portionof the volume of the enclosure. Prismatic shapes or irregular formfactors are very difficult to utilize since they will bow outward undereven modest fluid pressure. When absorbing materials (e.g. hydrides) areused, the mechanical strain on the internal tank walls can induce largestresses.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe substantially similar components throughout the several views.Like numerals having different letter suffixes represent differentinstances of substantially similar components. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in the present document.

FIG. 1 illustrates a cross-sectional view of a fluid enclosure,according to some embodiments.

FIG. 2 illustrates a cross-sectional view of a portion of a fluidenclosure utilizing a composite hydrogen storage material, according tosome embodiments.

FIG. 3 illustrates a cross-sectional view of a portion of a fluidenclosure utilizing a composite hydrogen storage material including afeature, according to some embodiments.

FIG. 4 illustrates a perspective view of a fluid enclosure, according tosome embodiments.

FIG. 5 illustrates a perspective view of a fluid enclosure system,according to some embodiments.

FIG. 6 illustrates a block flow diagram of a method of manufacturing afluid enclosure, according to some embodiments.

FIG. 7 illustrates a block flow diagram of a method of storing a fluid,according to some embodiments.

FIG. 8 illustrates a block flow diagram of a method of using a fluidenclosure, according to some embodiments.

SUMMARY

Embodiments of the invention relate to a fluid enclosure comprising astructural filler and an outer enclosure wall conformably coupled to thestructural filler.

Embodiments of the present invention further relate to a method ofmanufacturing a fluid enclosure. The method includes conformablycoupling an outer enclosure wall to a structural filler.

Embodiments of the invention relate to a method of storing a fluid. Themethod includes contacting a fluid enclosure with a fluid, wherein thefluid enclosure includes a structural filler and an outer enclosure wallconformably coupled to the structural filler. Embodiments further relateto a method of using a fluid enclosure. The method includes releasing afluid from a fluid enclosure, wherein the fluid enclosure includes astructural filler and an outer enclosure wall conformably coupled to thestructural filler.

Embodiments of the invention relate to a fluid enclosure system. Thesystem includes a fluid enclosure and an external device coupled to thefuel enclosure, wherein the fluid enclosure includes a structural fillerand an outer enclosure wall conformably coupled to the structuralfiller.

DETAILED DESCRIPTION

The following detailed description includes references to theaccompanying drawings, which form a part of the detailed description.The drawings show, by way of illustration; specific embodiments in whichthe invention may be practiced. These embodiments, which are alsoreferred to herein as “examples,” are described in enough detail toenable those skilled in the art to practice the invention. Theembodiments may be combined, other embodiments may be utilized, orstructural, and logical changes may be made without departing from thescope of the present invention. The following detailed description is,therefore, not to be taken in a limiting sense, and the scope of thepresent invention is defined by the appended claims and theirequivalents.

In this document, the terms “a” or “an” are used to include one or morethan one and the term “or” is used to refer to a nonexclusive or unlessotherwise indicated. In addition, it is to be understood that thephraseology or terminology employed herein, and not otherwise defined,is for the purpose of description only and not of limitation. In theevent of inconsistent usages between this document and those documentsso incorporated by reference, the usage in the incorporated referenceshould be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

Embodiments of the present invention relate to a fluid enclosure. Theembodiments of the present invention allow for a fluid enclosure inwhich a structural filler within the enclosure supports the stressapplied by the internal fluid pressure rather than having that pressurebe fully supported by the enclosure wall as is the case for traditionalfluid enclosures. The enclosure may include a structural filler with anouter enclosure wall conformably coupled to it. Since the outerenclosure wall bonds to the structural filler, the fluid pressureapplied to the enclosure is fully supported as isostatic tensile stressin the structural filler. The only significant stress that the outerenclosure wall experiences may be due to straining of the structuralfiller. The burst pressure of the enclosure is therefore limited to theultimate tensile strength of the structural filler or the bond betweenthe structural filler and the outer enclosure wall. This architectureallows compact, lightweight, and conformable fluid enclosures to bebuilt that can support significant internal pressures without theencumbrance of thick enclosure walls.

DEFINITIONS

As used herein, “fluid” refers to a continuous, amorphous substancewhose molecules move freely past one another and that has the tendencyto assume the shape of its container. A fluid may be a gas, liquefiedgas, liquid or liquid under pressure. Examples of fluids includehydrogen, methanol, ethanol, formic acid, butane, borohydride compounds,etc.

As used herein, “structural filler” refers to a material with asufficient tensile strength to withstand the internal pressure of afluid enclosure, when pressurized with a fluid. Structural fillers maybe solid. Structural fillers may include metallic or plastic lattices,composite hydrogen storage materials, clathrates, nano-structured carbonfoams, aerogels, zeolites, silicas, aluminas, graphite, activatedcarbons, micro-ceramics, nano-ceramics, boron nitride nanotubes,borohydride powder, palladium-containing materials or combinationsthereof, for example.

As used herein, “conformably coupled” refers to forming a bond that issubstantially uniform between two components and are attached in such asway as to chemically or physically bind in a corresponding shape orform. A structural filler may be conformably coupled to an outerenclosure wall, for example, in which the outer enclosure wallchemically or physically binds to the structural filler and takes itsshape.

As used herein, “outer enclosure wall” refers to the outermost layerwithin a fluid enclosure that serves to at least partially slow thediffusion of a fluid from the fluid enclosure. The outer enclosure wallmay include multiple layers of the same or differing materials. Theouter enclosure wall may include a polymer or a metal, for example.

As used herein, “feature” refers to a fluidic component associated witha fluid enclosure. A feature may act to communicate between an enclosureand an external device or ambient environment, to observe or control afluid, or act as a structural component. Examples of a feature may be avalve, regulator, pressure relief device, flow element, cap, fitting,vent, etc.

As used herein, “structural feature” refers to an element that may beassociated with the shape, positioning or alignment of the structuralfiller, the outer enclosure wall or the overall fluid enclosure. Astructural feature may be formed to allow space for external componentsor to create more efficient alignment between the fluid enclosure and anexternal device, for example. Structural features include convexprotrusions, concave recesses, mountings, flanges, fittings, bosses,smoothed or radiused corners, etc.

As used herein, “metal hydride particles” or “metal hydrides” refer tometal or metal alloy particles that are capable of forming metalhydrides when contacted with hydrogen. Examples of such metal or metalalloys are LaNi₅, FeTi, Mg₂Ni and ZrV₂. Such compounds arerepresentative examples of the more general description of metal hydridecompounds: AB, AB₂, A₂B, AB₅ and BCC, respectively. When bound withhydrogen, these compounds form metal hydride complexes, such as MgH₂,Mg₂NiH₄, FeTiH₂ and LaNi₅H₆, for example. Examples of metals used toform metal hydrides include vanadium, magnesium, lithium, aluminum,calcium, transition metals, lanthanides, and intermetallic compounds andsolid solutions thereof.

As used herein, “composite hydrogen storage material” refers to activematerial particles mixed with a binder, wherein the binder immobilizesthe active material particles sufficient to maintain relative spatialrelationships between the active material particles. Examples ofcomposite hydrogen storage materials are found in commonly-owned U.S.patent application Ser. No. 11/379,970, filed Apr. 24, 2006, now U.S.Pat. No. 7,708,815, whose disclosure is incorporated by reference hereinin its entirety.

As used herein, “clathrate” refers to a crystal formed from the bondingof a molecule with water. More generally, a clathrate may be alattice-type compound used to trap or hold another compound. A clathratemay be an organic addition compound comprising an internal space whichis enclosed. A clathrate may be formed by the inclusion of molecules incavities formed by crystal lattices or present in large molecules.Examples of clathrates include methanol clathrates, methane clathratesor hydrogen clathrates. The guest molecule may be held by the hostmolecule via physical, chemical or intermolecular forces. Host moleculesmay include urea, thiourea, hydroquinone, deoxycholic acid,triphenylcarbinol, perhydrotriphenylene, 18-crown-6 or 2,2,2-cryptand,for example. Examples of guest molecules include methanol, methane orhydrogen, for example.

As used herein, “polymer” refers to any of numerous natural andsynthetic compounds of usually high molecular weight consisting of up tomillions of repeated linked units, each a relatively light and simplemolecule. Examples of polymers include polypropylene, Kynar Flex®(vinylidene fluoride hexafluoropropylene copolymer), polyethylene,polyvinylidene fluoride (PVDF), hexafluoropropylene vinylidene fluoridecopolymer, cross-linked copolymers, polytetrafluoroethylene (PTFE),perfluoro alkoxy (PFA) and thermoplastic polyesters (for example,Nylon™).

As used herein, “forming” refers to creating, manufacturing, givingshape or any method that produces the desired end product from startingmaterials.

As used herein, “contacting” refers to physically, chemically orelectrically touching. A fluid may contact an enclosure, in which thefluid is physically forced inside the enclosure, for example.

As used herein “releasing” refers to freeing from something that binds,fastens or holds back, either physically or chemically. A fluid may bephysically released from an enclosure, for example. A fluid maychemically be released from a metal hydride, for example.

As used herein, “occlude” or “occluding” or “occlusion” refers toabsorbing or adsorbing and retaining a substance. Hydrogen may be thesubstance occluded, for example. A substance may be occluded chemicallyor physically, such as by chemisorption or physisorption, for example.

As used herein, “desorb” or “desorbing” or “desorption” refers to theremoval of an absorbed or adsorbed substance. Hydrogen may be removedfrom active material particles, for example. The hydrogen may be boundphysically or chemically, for example.

As used herein, “occluding/desorbing material” refers to a materialcapable of absorbing, adsorbing or retaining a substance and furthercapable of allowing the substance to be removed. The occluding/desorbingmaterial may retain the substance chemically or physically, such as bychemisorption or physisorption, for example. Examples of such a materialinclude metal hydrides, composite hydrogen storage materials,clathrates, etc.

Referring to FIG. 1, a cross-sectional view of a fluid enclosure 100 isshown, according to some embodiments. A structural filler 104 may besurrounded by an outer enclosure wall 102. The structural filler 104 maybe conformably coupled to the outer enclosure wall 102, which may berepresented by a bond 108. One or more optional features 106 may beutilized.

Structural Filler

The structural filler 104 may include a material with a sufficienttensile strength to withstand the internal pressure of the fluidenclosure 100, when pressurized with a fluid. Structural fillers may besolid. Structural fillers 104 may include metallic or plastic lattices,composite hydrogen storage materials, nano-structured carbon foams,aerogels, zeolites, silicas, aluminas, graphite, activated carbons,micro-ceramics, nano-ceramics, boron nitride nanotubes, borohydridepowder, palladium-containing materials or combinations thereof, forexample.

The structural filler 104 may include a material capable ofoccluding/desorbing a fluid, such as a metal hydride. This results in amaterial with sufficient tensile strength and fluid occluding/desorbingproperties, such as composite hydrogen storage material, nano-structuredcarbon foams, aerogels or zeolites, for example. In addition, the fluidenclosure 100 may include a structural filler 104 and a separate, fluidoccluding/desorbing material, such as a metal hydride powder orclathrate. For example, the structural filler 104 may be inert to thefluid being stored and the fluid enclosure may separately include afluid occluding/desorbing material. If a lattice, the structural filler104 may include small pores. Pores in the structural filler 104 may beused to hold fluid occluding/desorbing materials, such as metal hydridesor clathrates, for example. A methane clathrate may be used to storemethane efficiently at high pressure and could be used in conjunctionwith a structural filler 104, such as a metal lattice.

The structural filler 104 may be conformably coupled to the outerenclosure wall 102, creating a bond 108. As the force due to internalpressure within the fluid enclosure 100 increases, the load may betransferred directly into a tensile load on the structural filler 104,rather than internal pressure being amplified into tensile load on theouter enclosure wall 102. The internal pressure of the fluid enclosure100 may be affected by the amount of fluid stored. In addition, theamount of stress applied to the fluid enclosure 100 may be affected bythe mechanical stress associated with contacting/releasing a fluid froma storage material, such as hydrogen occluding/desorbing from a metalhydride, for example.

The structural filler 104 may have a continuous, uniform thicknessthroughout the fluid enclosure 100. Alternatively, the structural filler104 may include pockets or areas of discontinuous thickness or density,for example. One case may be where an irregularly shaped fluid enclosure100 calls for more structural support, such as in a corner, thestructural filler 104 may be more dense or include a greater portion ofthe available space within that area of the fluid enclosure 100.

Outer Enclosure Wall

The outer enclosure wall 102 may include a multitude of materials due tothe low stress applied to the outer enclosure wall 102. The outerenclosure wall 102 may include a polymer or metal or multiple layers ofeach, for example. The outer enclosure wall 102 may be polypropylene,Kynar Flex® (vinylidene fluoride hexafluoropropylene copolymer)(available through Arkema Inc, Philadelphia, Pa.), polyethylene,polyvinylidene fluoride (PVDF), hexafluoropropylene vinylidene fluoridecopolymer, cross-linked copolymers, polytetrafluoroethylene (PTFE),perfluoro alkoxy (PFA), thermoplastic polyesters (for example, Nylon™),or combinations thereof, for example. The outer enclosure wall 102 maybe formed of the same material as at least a portion of the structuralfiller 104, for example. The outer enclosure wall 102 may be a sheet ora solution, prior to application. The outer enclosure wall 102 does nothave to be rigid or in any pre-formed shape. The outer enclosure wall102 may act as a barrier to the exit of a fluid from the structuralfiller 104.

Because the structural filler 104 may be bonded to the outer enclosurewall 102, the stresses induced on the outer enclosure wall 102 becomeindependent of the geometry chosen. In conventional enclosure designs,the geometry of the enclosure strongly dictates the relationship betweenthe stress in the enclosure wall and the internal pressure. If astructural filler 104 is conformably coupled to the outer enclosure wall102, virtually any geometry of the fluid enclosure 100 may be utilized,so long as the tensile strength of the structural filler 104 and thebond 108 between the structural filler 104 and outer enclosure wall 102is larger than the internal pressure. The structural filler 104 may beformed into a desired shape before the outer enclosure wall 102 isconformably coupled to it.

The outer enclosure wall 102 may have a uniform or a varying wallthickness, for example. The outer enclosure wall 102 may have a greaterwall thickness around a feature, for example. The outer enclosure wall102 may have an average wall thickness of less than about 5000 microns,less than about 1500 microns, less than about 500 microns, less thanabout 300 microns, less than about 100 microns, less than about 50microns, less than about 10 microns or less than about 1 micron, forexample.

Referring to FIG. 2, a cross-sectional view of a portion of a fluidenclosure 200 utilizing a composite hydrogen storage material is shown,according to some embodiments. Active particles 204 are immobilized by abinder 206, making up the composite hydrogen storage material, which isan example of a structural filler 104. The outer enclosure wall 202penetrates within the interface region 208, conformably coupling to thestructural filler.

Interface Region

The interface region 208 includes the bond 108 between the structuralfiller 104 and outer enclosure wall 202 and may vary in thickness. Theouter enclosure wall 202 may be uniformly or near uniformly bonded tothe structural filler 104 so that a homogeneous or near homogenousinterface 208 may be formed, which prevents localized stressconcentrations building up at the outer enclosure wall 202. The outerenclosure wall 202 material may be applied to the structural filler 104and allowed to penetrate the surface, creating a bond 108 in theinterface region 208. The interface region 208 may become stronger thanthe structural filler 104, so that a failure of the fluid enclosure 300may be a failure from the structural filler 104 and not from the bond108 found at the interface 208. The interface region 208 may be lessthan about 50 microns, about 50-100 microns, about 100-150 microns,about 150-200 microns or more than 200 microns thick, for example.

Referring to FIG. 3, a cross-sectional view of a portion of a fluidenclosure 300 utilizing a composite hydrogen storage material includinga feature is shown, according to some embodiments. Active particles 204are immobilized by a binder 206, making up the composite hydrogenstorage material, which is an example of a structural filler 104. Theouter enclosure wall 202 penetrates within the interface region 208,conformably coupling to the structural filler. One or more features 302are positioned within the outer enclosure wall 202.

Features

The one or more features 302 may be adapted to control the movement of afluid into or out of the fluid enclosure 300, may observe or control thefluid or may be used as a structural component, for example. The one ormore features 302 may be used to communicate between the fluid enclosure300 and an external device, such as a fuel cell. Examples of a feature302 may be a valve, vent, cap, fitting, regulator, pressure reliefdevice, flow element (i.e., flow restrictor), etc. Examples of the oneor more features 302 may include fluidic components sold by Swagelok Co.or Beswick Engineering Co., for example. In the case where the featuremay be a pressure relief device, it may be a pressure-activated PRD or athermally-activated PRD. Further, it may be a self-destructive type PRD,such as fusible trigger, rupture disk or diaphragm, or a re-sealabletype, such as spring-loaded pressure relief valve (PRV). Alternately,the outer enclosure wall may be engineered to have a pressure relieffeature engineered in/integrated into the wall itself.

The one or more features 302 may be structural features associated withthe shape, positioning or alignment of the structural filler, the outerenclosure wall or the overall fluid enclosure. A structural feature maybe formed to allow space for external components or to create moreefficient alignment between the fluid enclosure and an external device,for example. Structural features may include convex protrusions, concaverecesses, mountings, flanges, fittings, bosses, smoothed or radiusedcorners, threaded standoffs, latching or locking features, etc.

The one or more features 302 may include safety enhancing aspects. Forexample, the feature may include a small, recessed valve that may onlybe activated with the proper tool. Further, an example may be featuresof such size as to make them inaccessible to inadvertent activation,such as small features within a recessed area. The one or more features302 may also include connecting hardware, in which the fluid enclosure300 may be coupled to an external device, such that duringconnecting/disconnecting of the fluid enclosure 300, little to noleakage occurs. Exemplary connecting hardware may be found, for example,in Adams, et al., U.S. Patent Application No. 2005/0022883, entitled“FUEL CARTRIDGE WITH CONNECTING VALVE,” the disclosure of which isincorporated herein by reference in its entirety.

Referring to FIG. 4, a perspective view of a fluid enclosure 400 isshown, according to some embodiments. The fluid enclosure 400 displayedincludes a largely prismatic form factor including a concave feature 402and convex feature 406, such as a protrusion. The concave feature 402may be utilized to accommodate an external valve or pressure regulator,for example. The convex feature 406 and rounded corners 404 may beutilized such that the fluid enclosure 400 may fit an available space,such as that provided by an external device, for example. The convexfeature 406 may also be used to lock, latch or securely hold the fluidenclosure 400 to or within an external device. Some structural features,like the convex feature 406, allow for the dual function of fluidstorage and efficient alignment/positioning of the fluid enclosure 400.

Fluid Enclosure Shape

The fluid enclosure 400 may have a regular or irregular shape. Regularshapes may include cylindrical, prismatic, or polyhedral shapes (i.e.,tetrahedral shapes), for example. Irregular shapes may be chosen toconform to fitting within a confined volume or space available, such asto fit within the interior volume of an enclosure of an electronicdevice. Irregular shapes may also be chosen so as to accommodatefeatures, such as external fittings or fluid control devices. Other formfactors, such as irregularly shaped polyhedrons, for example, are alsopossible.

Fluid Enclosure System

Referring to FIG. 5, a perspective view of a fluid enclosure system 500is shown, according to some embodiments. The fluid enclosure system 500includes a fluid enclosure 400 coupled to an external device 502. Theconvex feature 406 and rounded corners 404 of the fluid enclosure 400may be utilized such that the fluid enclosure 400 may fit the availablespace provided by the external device 502. Examples of an externaldevice 502 may be a fuel cell, heat pump, battery, compressor or airconditioning unit, for example. Further, the external device mayadditionally be coupled to an electronic device, such as a portableelectronic device, or to the electronics of an electronic device.Examples of portable electronic devices include cellular phones,satellite phones, PDAs (personal digital assistants), laptop computers,computer accessories, displays, personal audio or video players, medicaldevices, televisions, transmitters, receivers, lighting devicesincluding outdoor lighting or flashlights, and electronic toys.

The concave feature 402 may house such features 504, 506 as connectors,valves or regulators, for example. The concave feature 402 may alsoprovide a space for electronic/power conditioning associated with a fuelcell power pack.

Referring to FIG. 6, a block flow diagram of a method of manufacturing600 a fluid enclosure is shown, according to some embodiments. An outerenclosure wall 602 may be conformably coupled 604 to a structural filler606.

Conformably Coupling

The outer enclosure wall 602 may be conformally coupled 604 to thestructural filler 606 by a variety of methods. Such methods includespraying, painting, dip coating, inset molding, electrostaticdeposition, compression molding, transfer molding, injection molding,thermoset injection molding, extrusion, pultrusion, thermoforming, etc.The wall thickness may be increased by duplicating the coupling processor using a different coupling process in order to create multiplelayers. Not only can multiple layers of the outer enclosure wall 602 beapplied, but one or more layers of other materials may be added. Forexample, if a thin outer enclosure wall is formed, fluid may slowlydiffuse through the wall. A sealing layer may be applied to prevent suchdiffusion. Examples of a sealing layer may be a thin metallic layer,such as aluminum, copper, gold or platinum. The outer enclosure wall 602may be comprised of the same or similar material as the structuralfiller 606, or a portion of the structural filler 606, in order toincrease the bond strength, for example. The layers may be heated orsintered after application.

One or more features, including but not limited to structural features,may be formed in the structural filler 606, formed with the outerenclosure wall 602 or formed during the coupling of the structuralfiller and outer enclosure wall. Examples of such features includefittings, regulators, fasteners, mounting flanges, bosses, valves,vents, caps, flow elements, etc.

Fluid Enclosure Size/Volume

Embodiments of the invention allow for a fluid enclosure or fluidenclosure system to be manufactured at sizes not previouslycontemplated. Although readily usable at large sizes, the fluidenclosure may be as thin as less than about 10 mm, for example, Thefluid enclosure may have a volume of less than about 1000 cm³, less thanabout 500 cm³, less than about 120 cm³, less than about 10 cm³, lessthan about 5 cm³, less than about 2 cm³ or less than about 1 cm³, forexample. A fluid enclosure system, including an external device, may beless than about 1000 cm³, less than about 500 cm³, less than about 120cm³, less than about 25 cm³, less than about 15 cm³, less than about 10cm³ or less than about 5 cm³ for the total system, for example.

Storing Fluid

Referring to FIG. 7, a block flow diagram of a method of storing 700 afluid is shown, according to some embodiments. A fluid enclosure 702 ofthe embodiments of the present invention may be contacted 704 with afluid, sufficient to provide a fluid enclosure storing fluid 706. Thefluid may then be stored for a desired amount of time. After contacting704 the fluid enclosure 702, the fluid may be released. After releasingthe fluid, the fluid enclosure 702 may be contacted again with fluid.The fluid enclosure 702 may be contacted with a fluid and released offluid multiple times. The fluid enclosure may be contacted with a fluidand the fluid released once, at least about 3 times, at least about 50times, at least about 300 times, at least about 500 times, at leastabout 1000 times or at least about 10,000 times, for example.

Using Fluid Enclosure

Referring to FIG. 8, a block flow diagram of a method of using 800 afluid enclosure is shown, according to some embodiments. A fluidenclosure storing a fluid 802 may release 804 a fluid. Releasing 804 allor a portion of the fluid from the fluid enclosure storing a fluid 802provides a fluid enclosure 806 which may contain less fluid. The fluidenclosure storing a fluid 802 may be coupled to an external device, suchthat the fluid is released 804 to the external device for its use or topower the device, for example. Examples of an external device may be afuel cell, heat pump or electrolyser. The fluid enclosure may alsoaccept fluid from an external device coupled to it, such as anelectrolyser, or waste fluid from some types of fuel cells (i.e. spentelectrolyte from a direct borohydride fuel cell, CO₂ produced from anyhydrocarbon fuel based fuel cell, such as a formic acid fuel cell,direct methanol fuel cell, reformed methanol fuel cell, etc.).

After releasing 804 the fluid, the fluid enclosure 806 may be contactedwith a fluid. The fluid may then be released again. The releasing andcontacting of fluid to the fluid enclosure 806 may be repeated multipletimes. The releasing and contacting of fluid to the fluid enclosure mayoccur once, at least about 3 times, at least about 50 times, at leastabout 300 times, at least about 500 times, at least about 1000 times orat least about 10,000 times, for example.

Embodiments of the present invention describe a fluid enclosure that maybe used in a portable galvanic or electrochemical cell, such as a fuelcell system, as a fuel reservoir. Other embodiments describe a fluidenclosure that may be used as a storage reservoir for use in a device,such as in heat pumps, hydrogen compressors or air conditioners, forexample. Some examples of portable electronics for use with the fuelcell include, but are not limited to, cellular phones, satellite phones,PDAs, laptop computers, computer accessories, displays, personal audioor video players, medical devices, televisions, transmitters, receivers,lighting devices including outdoor lighting or flashlights, electronictoys, or any device conventionally used with batteries.

The present invention will now be described with the followingnon-limiting examples.

EXAMPLES Example 1

Wafers of a structural filler made from a composite hydrogen storagematerial were formed by heat and pressure sintering as detailed in U.S.patent application Ser. No. 11/379,970, now U.S. Pat. No. 7,708,815,with densities between about 5 glee and about 6.1 g/cc. The wafers withdensities from about 5 to about 5.5 glee included about 6% by weight ofKynar Flex® 2851 as a binder. Wafers with densities of about 5.5 toabout 6.1 g/cc included about 4% by weight of Kynar Flex® 2851 as abinder, The wafers were substantially free of dust and weresubstantially free of surface roughness features exceeding about 50microns (μm, or 10⁻⁶ m).

Components were attached using a Kynar Flex® interface. A solventsolution of about 40 to about 80 g/L Kynar Flex® 2751 was used as a gluefor connecting the components to the enclosure. A fluid port or openingwas fitted with a 2-micron filter and a small hole (about 0.8 micron)was drilled into the wafer (about 7 microns) to facilitate fluiddiffusion into and out of the enclosure.

Kynar Flex® 2851 dissolved in acetone was applied as a coating inmultiple layers. The first layer was applied by dipping a wafer into asolution of about 40 g/L Kynar Flex® 2851 dissolved in acetone. Thesolution then penetrated the surface pores of the wafer. Subsequentlayers were painted on using about 80 g/L Kynar Flex® 2851 in acetoneand were allowed to fully dry between applications. A total of about 20to about 30 mg/cm² of coating was disposed uniformly on the wafer. Afterdrying, the remaining coating (outer enclosure wall) was about 100 toabout 150 microns thick. The fluid enclosure was then sintered at about190° C. for about 20 minutes.

Example 2

A prismatic format block of a composite hydrogen storage material wasformed with dimensions of about 5 cm×3 cm×0.5 cm, corners were radiusedand smoothed. Two sheets of polypropylene were formed with approximatedimensions of the prismatic block and placed on either side of theprismatic format block. The three layer structure was then isostaticallypressed at about 150 psi (1.03 MPa or about 1 MPa) and heated to about180° C. for about 30 minutes. Once cooled, the polypropylene sheets hadbeen conformably bonded to the structural filler. An opening was cut into the conformably formed enclosure wall, and a gas fitting inserted andheld in place with adhesive material.

Example 3

A similar prismatic format block of composite hydrogen storage material,as in Example 2, was formed. RTV Silicone (Dow Corning) was applied as acoating of a thermoset elastomeric polymer. The coating was applied andcured at about 120° C.

The Abstract is provided to comply with 37 C.F.R. §1.72(b) to allow thereader to quickly ascertain the nature and gist of the technicaldisclosure. The Abstract is submitted with the understanding that itwill not be used to interpret or limit the scope or meaning of theclaims.

All publications, patents, and patent documents referenced herein areincorporated by reference herein in their entirety, as thoughindividually incorporated by reference.

1. A fluid enclosure comprising: a structural filler capable ofoccluding and desorbing hydrogen; and an outer enclosure wallconformably coupled with the structural filler.
 2. The fluid enclosureof claim 1, wherein the structural filler includes a metal hydride. 3.The enclosure of claim 2, wherein the structural filler is a compositehydrogen storage material.
 4. The enclosure of claim 1, wherein theouter enclosure wall includes multiple layers.
 5. The enclosure of claim1, further including one or more sealing layers conformably coupled tothe structural filler.
 6. The enclosure of claim 1, wherein thestructural filler supports a tensile stress applied by an internal fluidpressure.
 7. A fluid enclosure comprising: a structural filler capableof occluding and desorbing a fluid; and a flexible outer enclosure wallconformably coupled to the structural filler.
 8. The fluid enclosure ofclaim. 7, wherein the structural filler includes a metal hydride.
 9. Theenclosure of claim 8, wherein the structural filler is a compositehydrogen storage material.
 10. The enclosure of claim 7, wherein theouter enclosure wall includes multiple layers.
 11. The enclosure ofclaim 7, further including one or more sealing layers conformablycoupled to the structural filler.
 12. A fluid enclosure comprising: astructural filler capable of occluding and desorbing a fluid; and anouter enclosure wall coupled to the structural filler at an interfaceregion, wherein the interface region includes an outer enclosure wallmaterial that is penetrated into a surface of the structural filler. 13.The fluid enclosure of claim 12, wherein the structural filler includesa metal hydride.
 14. The enclosure of claim 13, wherein the structuralfiller is a composite hydrogen storage material.
 15. The enclosure ofclaim 12, wherein the interface region is substantially homogeneous incomposition of structural filler and outer enclosure wall material. 16.The enclosure of claim 12, wherein the outer enclosure wall includesmultiple layers.
 17. The enclosure of claim 12, further including one ormore sealing layers conformably coupled to the structural filler.
 18. Amethod of storing hydrogen comprising: directing hydrogen into a fluidenclosure, wherein the fluid enclosure includes a structural fillercapable of occluding and desorbing the hydrogen and an outer enclosurewall conformably coupled to the structural filler; and occluding thefluid onto the structural filler.
 19. The method of claim 18, whereinthe structural filler includes a metal hydride.
 20. The method of claim19, wherein the structural filler is a composite hydrogen storagematerial.
 21. The method of claim 18, wherein the outer enclosure wallincludes multiple layers.
 22. The method of claim 18, further includingone or more sealing layers conformably coupled to the structural filler.23. The method of claim 18, wherein the structural filler supports atensile stress applied by an internal hydrogen pressure.
 24. The methodof claim 18, wherein the outer enclosure wall is flexible.
 25. Themethod of claim 18, further including an interface region that includesan outer enclosure wall material that is penetrated into a surface ofthe structural filler.